Let There Be Light!

I’ve been experiencing a gambit of emotions during this chemistry class. From, “this is so challenging and fun!” to “I can’t believe I signed myself up for this??” to “okay, if I work really hard I can figure this out,” to finally this week something between wild elation and overwhelming trepidation. Haha, who know a chemistry could incite so many feelings?

Anyways…the class this week is introducing the concept of quantum physics and the atomic nature of light! Has anyone wondered, “what exactly is light?” This has been a familiar topic of thought for me, although I think my favorite is to ponder the essence of water as I stare at a glass of it. I actually do that quite often. Haha, that sounds very strange, so…moving on to light! The exact formulas for doing calculations about electron energy in different orbitals is still quite daunting, but I am happy to say I’ve developed a very lovely explanation for the concept! So, if you have no prior knowledge of electrons, quantum physics, etc…my eccentric metaphor might be helpful! Here goes:

Imagine a tall apartment building. The ground floor of this building is actually underground, and it happens to be in a very foggy area, so because of its height, you can’t actually see the top few floors. In this building there reside music-loving electrons. These electrons are easy-going blobbish looking things. In my mind I have some really cute ideas of what these electrons look like, but I’ll save that for another time. They prefer to live closest to the ground (warmer, and less stairs) but of course this space is limited, so if there are too many electrons, they have to take the higher floors. Remember, I said these electrons love music? Well, one day someone decides to make their day, and begins blaring Mumford and Sons music right outside their apartment building. Some people might find this annoying, but of course these electrons love it! In fact, they get so excited, they start jumping up and down. And the electrons on the bottom floor are so happy they go running upstairs (this has a dual purpose, to hear the music better and to do something with their energy). But, unfortunately they can’t stay on the upper floors because that’s not their apartment, so they have to try to calm down and return to their own place. The joy of the music is so overwhelming though that they find themselves singing along as they go back downstairs. And that’s how light is emitted!

And you’re probably thinking, “uh…that makes no sense at all.”

Okay, I’ll explain.

The apartment building is an atom. Atoms have different numbers of electrons, so for some atoms only their ground floor is filled, and for others most of the floors are occupied. But they all want the lowest floor possible (this puts them in a lower energy state, which is what everything naturally wants). When energy is added to the system (like blaring Mumford and Sons) using things like heat or light, the electrons get excited (yes, this is actually the official term) and jump up to another floor. But the electrons then spontaneously return to their original and lower states by relaxing. When they’re going from the higher state of energy to the lower state, they have to do something with the energy they’re losing, so it is emitted in the form of photons, and that is essentially what we know of as light. Now, remember in my example, the ground floor was actually like a basement. So if someone is going from the second floor to the first floor (aka, above ground to basement) you can’t see them doing that. Likewise, because of the fog and building height, you can’t really see any movement on the higher floors. What does this really mean? When electrons go from a higher energy state all the way down to the ground state (1), this is ultra-violet light. When electrons go from a higher state down to the second state (2), this is visible light, and when they go from a higher state down to the third state (3), this is infrared light.

Isn’t this just stunning? That all the light we see is basically photons being emitted from electrons as they relax from their excited state? This is an epiphany along the same lines as when I watched Khan videos a few years ago and realized that everything is made out of atoms which are mostly nothing (there’s very little mass in an atom) and yet there’s all this stuff. In other words, life-changing. This makes me think about the world in a totally different way. And that’s why I love learning. This chemistry class has challenged me to enjoy long hours of studying just so you know that you’ve mastered a concept, but I absolutely love these rare but beautiful moments of epiphany when your world is transformed by newly gained knowledge. That’s why I’ll never stop learning. : )